With the widespread use of information terminals, the need for flat panel displays as displays for computers has grown. Moreover, with the development of computerization, the number of occasions where information, which has been offered in the form of paper media in the past, is converted into electronic form is increased, and there is also a growing need for electronic paper or digital paper as a mobile display medium which is thin and light and allows it to be carried around easily.
In general, in flat-shaped display devices, a display medium is formed by using elements utilizing liquid crystal, organic EL (organic electroluminescence), electrophoresis, and the like. Moreover, in such a display medium, in order to ensure the uniformity in screen brightness, a screen rewriting speed, and so forth, the technology using active driving elements (TFT elements) as image driving elements has become the mainstream. For example, in an ordinary computer display, these TFT elements are formed on a glass substrate and the liquid crystal, the organic EL element, and so forth are encapsulated.
Here, in the TFT element, semiconductors such as a-Si (amorphous silicon), p-Si (polysilicon), and the like are mainly used, and these Si semiconductors (and metal films, if necessary) are stacked in layers and source, drain, and gate electrodes are sequentially formed on the substrate, whereby the TFT element is produced. For the production of such a TFT element, it is generally considered that high-temperature or high-vacuum production processes such as sputtering, plasma CVD, and photolithography are necessary.
Since the above-described existing formation of the TFT element using the Si materials includes a process which is performed at high temperature, the constraint that a substrate material is a material which endures the process temperature is sometimes added to the substrate material. Therefore, in actuality, a substrate, such as glass, which has high resistance to heat, plasma, and light has to be used, and, if a thin display such as the electronic paper or digital paper described above is configured by using such a known TFT element, the display becomes a product which is heavy, lacks in flexibility, and may be broken by a drop impact.
These characteristics caused by the formation of the TFT element on the glass substrate are undesirable in filling the need for an easy-to-use portable thin display, the need which arises with the development of computerization.
On the other hand, in recent years, as organic compounds having high charge transport capability, a study of organic semiconductor materials has been conducted intensively. An attempt has been made to apply these compounds to an organic laser oscillation element and an organic thin-film transistor element (organic TFT element) in addition to a charge transport material for an organic EL element.
Producing an organic thin-film transistor element by an inkjet method by turning an organic semiconductor material into ink as a solution has also been studied (Patent Document 1).
In the past, a printing production line system for an electronic device, the printing production line system which produces an electronic device such as an organic thin-film transistor element by using a printing method, has not been fully established.
Patent Document 2 discloses the technique of providing one processing chamber for a robot transport chamber.
However, this technique is a so-called one-to-one processing technique with a 1-to-1 transport chamber-to-processing chamber ratio and has no technical idea of a printing production line.
Therefore, a printing production line system for an electronic device is not disclosed at all in Patent Document 2 and it can be said that Patent Document 2 is an existing example in which the printing production line system is not fully established.
Patent Document 3 discloses that a transport container such as a FOUP is used when wafers are transported. Moreover, in paragraph 0011, Patent Document 3 makes the following disclosure “wafers are housed in a transport container such as a FOUP (Front-Opening Unified Pod) and transported in a facility in a hermetically sealed state. For this reason, a transport chamber with a high level of cleanliness is not provided, . . . ”. This technique of Patent Document 3 is a so-called 1-to-n processing technique with a 1-to-n transport chamber-to-processing chamber ratio.
In the technique of Patent Document 3, a base material such as a wafer is transported to a processing chamber in a state in which the base material is housed in a hermetically sealed container, which is opened in the processing chamber and processing is performed, and, after being processed, the base material is hermitically sealed and transported to a processing chamber in a different location.
However, although the technique of transporting a base material to a processing chamber in state in which the base material is housed in a hermetically sealed container is considered to be capable of contributing to prevention of the occurrence of defective products caused by dust in the course of transport of a substrate to a processing chamber from a transport chamber, this technique has the drawback of the necessity for an operation to open the hermetically sealed container in the processing chamber and a resultant increase in the number of man-hours on a production line. Moreover, when the base material is transported to another processing chamber after being processed, an operation to house the base material in the hermetically sealed container again becomes necessary and this operation itself to hermitically seal the base material undesirably increases the number of man-hours.
As described above, the technique of Patent Document 3 undesirably increases the number of production man-hours and therefore cannot be applied to a printing production line for an electronic device, the printing production line which is required to have high productivity.